Eye Rays: Argons possess four eyes spaced about what could be generously described as its body (in addition to their central eye on the front). Each eye grants the argon access to an arcane talent that the argon can use at will (no Fatigue cost). The eyes can extend on a fleshy stalk a few feet in length, which allows the argon to focus multiple eyes on a single target that it otherwise couldn't (or peek around corners/through small openings to spy on others).

(Considering making it so that extended eyes can be damaged and destroyed. Not sure how I wanna do this, though: could see it as a called shot that requires a slashing weapon and 5 points of damage to sever, but then players might want to called shot other things. I guess if you're doing something like Dungeon World then the messy tag is enough to get rid of them.)

Antimagic Eye: The central eye of an argon negates all arcane magic within a 60 feet cone that it can see.

The origins of argons would depend on your campaign (if you even want to define them). Maybe they come from a place where wizards have modified themselves such that they no longer needed the rest of their bodies, and are basically floating heads with a bunch of magic eyes. They could also come from another plane of existence (like the Far Realm), another planet, or even another timeline.

I think it would also be cool if they had collections of eyes with various magical powers that they could swap out from time to time. Some might work together, even sharing or trading eyes, but others would try and kill each other in order to gather up their eyes to add to their collection. I could also see them targeting wizards, using a process involving the wizard's eyes and brain to create new magic eyes.

To randomly determine eyes I'd make a big-ass table, but the GM can also just choose specific powers if they want.

Obviously you can give argons more eyes, but you could also base it on size: Large argons have 5-8 eyes, Huge argons have 9-12 eyes, and Gargantuan argons can have 13-16 eyes. Could even have it so that a Large argon is really two argons fused together (willingly or otherwise), a Huge argon is three, etc.

Arcane Talents

Obviously most argons would have access to various wizard talents. Just give them whichever ones you want, but since these would function normally (ie have a Fatigue cost) you'd also give them 4 Mana per level.

(For other games, just tack on wizard or sorcerer levels.)

Uses for Argon Eyes

The central eye of an argon can be made into an amulet or circlet that grants its wearer a +1 bonus to all saves made against arcane magic. If the spell requires an attack roll, you gain a +1 bonus to Armor Class, and if it inflicts damage, it is reduced by 1 (to a minimum of 0).

Other argon eyes can be made into a wand or ring that grants its wielder access to that arcane talent: they don't need to meet the perquisites for that talent, but must have at least one wizard level and pay the Fatigue cost as normal.

Multiple argon eyes can be incorporated into a staff or crown that allows its wielder access to any arcane talents that the eyes could use.

(For other games, the eyes make a wand/staff that lets you use those spells, either with charges or x times per day.)

Announcements

If you're curious about FrankenFourth and/or Dungeons & Delvers, you can find public alpha documents here and here respectively.The Rogueis our latest alternate-addition to the Dungeon World core class roster. If you want something different and/or more flexible than the thief, be sure to check it out!

Just released our second adventure for A Sundered World, The Golden Spiral. If a snail-themed dungeon crawl is your oddly-specific thing, check it out!

@Victor: Initially I was thinking that only on a crit would be too unreliable.

But, 2E D&D handles this with a called shot rule, 4E and 5E don't give you anything at all, so maybe that's the way to go? You don't normally get to hack off an eyestalk, but hey if you crit it's an added bonus!